So many sites, so many choices! It is hard to resist if one is looking forward to investing his idle Bitcoins. There is no certain way to know if a web wallet or a site promising some juicy interest will ever pay back. There are warning signs though. The swindlers' business model is simple - temptation. You want to test if they pay back as promised before you invest big bucks. You invest the required minimum knowing that you will not miss such a small amount, just to test it, and... you lose! Even if you get paid back your initial investment you will probably never see your second larger deposit. Just a few examples of sites which disappeared with depositors' money - itcoin.biz and  bitcoinera.net, Let me be clear. This article is not about a legitimate business such as Bitbond Bitcoin lending marketplace. This is about sites which promise to pay interest on your deposits or outright doubling your money.

The first sign is rather obvious - the interest rate. If anyone says they will pay more than 10 % per year then it sounds to good to be true. The next thing worth checking is the length of time the a site has been around. This can be done by checking domain registration records of the site you plan to entrust your coins to. It can be done by querying Internet "whois"  records. You can do it here. Review the results for things like - the registration date, the renewal date, was the domain registered by a company or a person, is the owner listed or anonymous? 

A recent registration date will tell you that the site is new and not enough time has passed to indicate that this is a long term business. Most likely a fly-by-night operation.

A renewal date of no more than 1 year tells you they don't plan to stick around for too long.  

An absence of a corporate identity or anonymous domain owner is a clear indication of something to hide. 

A quick look at the domain registration record can tell a lot and save you some disappointment.