The guy (or girl for all you know) across the digital table from you has gone all-in. It is too early in the tournament for you to know if he/she is a good player or just a wild gambler. What if you could get a little more information? That's where SharkScope comes in.
SharkScope.com is a search able on-line database of all the players from PokerStars, FullTilt, PartyPoker and other sites. It lists their average stakes, their return-on-investment, how many games they have played, and overall profitability. If the player you look up has a profit of say, -$2,000, there is even a cute fish icon next to their name.
Look yourself up to see how it works. You get five free searches a day, then you have to pay. Personally, I've only been getting a game in here and there lately, so free has worked for me. This "background check" is extremely valuable if you are a single-table tournament player as the stats reflect those games.
Safe bets aside, gambling is good as long as the stakes are not high. This is why people love lottery and online poker.