Did you mention your summer holiday on Facebook? Did you check in from the beach? Have you ever written an update revealing details about your bank, internet provider or mobile phone? Then you could be in for a nasty surprise, because the experts are warning that all of these could potentially persuade an insurer or bank to reject any claim you make.
So how could they justify it?
The issue has arisen because so many people have started to share so much information online. The insurance industry is concerned that the details people pass onto their network - and sometimes to the wider world - could leave them open to attacks from criminals from car thieves to burglars and scammers.
Take a summer holiday, for example, if you tell everyone when you are away and where you are going, and then check in from the airport, insurers may take a very dim view if you are subsequently burgled. They may argue that you have advertised your empty home to thieves.
Nick Starling, the ABI's Director of General Insurance and Health, points out: "Unoccupied summer homes are already more vulnerable to burglary, without advertising online that you are away. With criminals increasingly going online to access personal details, avoid divulging personal information, such as your holiday plans, online."
Claire Foster, spokesperson for Churchill home insurance, agrees: "Our customers are covered whether they tell people where they are or not. However, common sense dictates that you should avoid advertising to opportunistic thieves where you are. To return home and discover you have been broken into is an awful experience for anyone to endure."
Likewise, if you post a photo of your car outside your house, or any valuable belongings inside, you may be advertising your possessions to thieves. We recently reported about a young woman who had her parents' home in Australia robbed by people who'd seen her Facebook page. She'd been helping her grandmother count a load of cash, taken a picture of it and uploaded it. Thieves found out where she lived and broke in.
And if you give out details of contracts you hold such as broadband or mobile phones, you can open yourself up to risks from scammers pretending to be from these firms. They may contact you, asking you to click on links embedded in emails. These links would then take you to fake pages which could either infect your computer with malware, or directly encourage you to reveal personal details.
The risks are particularly high where people have left their profile public, so that anyone could read about their exploits. However, even when it is restricted to friends, those with hundreds of connections cannot always be sure they are all trusted friends.
Earlier this year, Confused.com predicted the new wave in social media could eventually lead to big hikes in home insurance premiums. Gareth Kloet, head of home insurance at Confused.com said: "What's happened in the US could be the start of a worrying trend and if insurance providers see it as a potential risk, you can bet your home contents on the fact they'll start pricing for it. Something like 'Places' on Facebook broadcasts people's locations on a platform which has 500 million users - you don't need to be an insurance provider to see the risk that poses. I wouldn't be surprised if we see rises of up to 10% for social media users in the future."
Refuse to pay
However, the latest concern is that if you make too much information available, your insurer or bank could consider you to have been 'grossly negligent' and in these instances they would refuse to pay out any claim - or your bank could refuse to refund money scammed from you.
At the moment the industry is dealing with each case on its own merits. However, many have said they will not pay out where someone has been 'reckless' with information. Oliver Crofton, director of online security company Vigilante Bespoke told the Daily Mail that social networking is likely to be considered far more often by the industry within the year.
He said: "Hackers now use a more targeted approach, digging deeper and using social media. People put an alarming amount of personal information on different sites and everything you update, you broadcast to the world. This is costing the banking industry so much at the moment that it is an inevitable development that they will get stricter."
10 of the biggest consumer rip-offs
Could Facebook mean your insurance claim is rejected?
Using a mobile phone to make and receive calls, send texts and browse the web while abroad can be extremely costly – especially if you are travelling outside the European Union (EU), where calls can cost up to 10 times as much as at home.
To avoid high charges, Carphone Warehouse suggests tourists ensure a data cap is in place, use applications to check data usage, turn off 'data roaming', avoid data-intensive applications such as Google Maps and YouTube and use wi-fi spots to update social networking sites.
Payment Protection Insurance (PPI) is supposed to help people to continue meeting their loan, mortgage or credit card repayments if they fall ill or lose their jobs. However, policies are often over-priced, riddled with exclusions and sold to people who could not make a claim if they needed to.
At one point, sale of this cover - which was often included automatically in loan repayments - was estimated to boost the banks' profits by up to £5 billion a year.
Now, though, consumers who were mis-sold PPI can fight back by complaining to the bank or lender concerned and taking their case to the Financial Ombudsman Service (08000 234567) should the response prove unsatisfactory.
It could be you, but let's face it, it probably won't be. In fact, buying a ticket for the Lotto only gives you a 1 in 13.9 million chance of winning the jackpot.
With odds like that, you would almost certainly be better off hanging on to your cash and saving it in a high-interest account.
No-frills airlines such as EasyJet may promote rock-bottom prices on their websites. But the overall fare you pay can be surprisingly high once extras such as luggage and credit card payment fees have been added - a process known as drip pricing.
Taking one piece of hold baggage on a return EasyJet flight, for example, adds close to £20 to the cost of your flight, while paying by credit card increases the price by a further £10.
It may therefore be worth comparing the total cost with that of a flight with a standard airline such as British Airways.
Cash advances, which include cash withdrawals, are generally charged at a much higher rate of interest than standard purchases.
While the average credit card interest rate is around 17%, a typical cash withdrawal of £500, for example, is charged at more than 26%.
What's more, as the interest accrues from the date of the transaction, rather than the next payment date, costs will mount up even if you clear your balance in full with your next payment.
Supermarkets such as Tesco and Asda often run promotions under which you can, for example, get three products for the price of two.
However, it is only worth taking advantage of these deals if you will actually use the products. Otherwise, you are simply buying for the sake of it, which is a waste of your hard-earned cash.
Buy a train ticket at the station on the day of travel and the price is likely to give you a shock - especially if you are travelling a long distance at a busy time of day.
However, you can cut the cost of train travel by 50% or more by going online and making the purchase beforehand - especially if you book 12 weeks in advance, which is when the cheapest tickets are on sale.
Other ways to reduce the price you pay include avoiding peak times and taking advantage of so-called carnet tickets, which allow you to buy, for example, 12 journeys for the price of 10.
Most High Street banks offer packaged accounts that come with monthly fees ranging from £6.50 up to as much as £40, with a typical account charging about £15 per month.
Various benefits, such as travel insurance and mobile phone insurance, are offered in return for this fee. But whether or not it is worth paying for them depends on your individual circumstances.