I seem to have pretty good online radar, all the guys I met looked pretty much like their pictures and were pretty much as advertised.
Although there were a few scammers online - one guy who was always out of town on business and who claimed to be a jeweler - I put the pictures he sent me through Tineye, turned out they were pics of the Titanic movie jewels lol. Find out quickly if there's chemistry or not, and if they're weird or not.