Not true. If it were, many people would still not be trying to get into it. Easier to get the true value of your site in adult, then low ballers in mainstream who think they can offer 6-10 months of income like it's a legit offer. It isn't. Many need to learn the real value of internet property. Both sites, and domains. There is not any 'rule' of 3, 6, 10 months of revenue for any site. Ever. There are many factors that go into evaluating an asset. It frankly amazes me on some of the offers people give with a straight face (because they have no money) or desperate people will accept. If people are needing cash in a pinch, I can't fault them. But many around DP, and the boards are low ballers, and that is where you run into problems selling property. But I digress...
Well said ^^ - and the web sites that boast that they're so cheap and make $xxxx a month and will sell for a months profit are generally inflated with junk traffic with the goal of boosting the sales price - after the sale the buyer is often left with junk.