Bitcoin faucets are a reward system that dispenses rewards in the form of a satoshi for visitors to claim in exchange for completing a captcha or task as described by the website. So, you have to come to site, solve antibot and click claim button.
It seems so easy, but is it really?
Lets see, you open site, you wait some time because all ads are causing site to open very slow. Now you enter your bitcoin address, solve captcha, find antibot numbers or letters and hit claim button for small price of 100-500 satoshi. Repeat with second faucet, third....And after 8 hours doing this you made some progress - you see that you have 0.001BTC. Is it really worth of time? I don't think so.
FAUCET RISKS
1. LOTS OF DUST TRANSACTIONS MAKE LARGE FEE's LATER
Every time you receive a bitcoin payment to your wallet you have a new input to spend. More inputs, larger size and you will pay very high fees at the end.
2. SCAM
Some faucet owners find that not paying is much easier than paying. So you finally hit that withdraw limit, and hit cashout button, but you never receive coins to your wallet. And after all your hard work you see that you actually lost hours and hours and days for actually nothing.
3. MALICIOUS ADS
Not all advertising companies/sites are verifying ads from users. Some ads are able to infect a machine with malware, and when doing faucet ad-blockers are something you can't use. Be careful, and run your AV very often.
4. BOTS AND SCRIPTS
Some faucets offer you to download bots scripts or something third, and when you do that you have very good chance to get infected with malware. Keylogers will steal your personal infos, wallet passwords etc.