My ex room mate got onto the Internet way back when, when they would charge per minute (He would get phone bills of $300+ per month
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). He started quickly learning HTML and set up web pages which were basically blogs (political discussion) before blogs were in vogue.
Since then, he ran maybe five sites, mostly for fun and some informational ones and such (He gained trusted posters who could keep adding to his site with articles which sustained return viewers). When he and his family ran into dire financial straights he was able to sell one of his sites for between $30,000 - $40,000.
I don't really visit his sites, but he gets a cheque each month getting money for page references, some kind of hot word, google thing, and possibly some add revenue. Not anything significant ($200-$400 per month), but he's done some research and gone to school to learn how to increase your website's viewership and google listing (he helped our company's web site google listing when we first started 10 yrs ago).
So you never know.....something started for fun may pay off in the future.