Followings are some disadvantages of Free Web Host.

# Search engines often ignore them A HUGE disadvantage!
# May have banners and/or pop ads on your homepage and/or all of your pages.
# No guarantees of site availability and longevity.
# Poor help and support options (if any).
# Can't add interactive features (chat rooms, message boards, games, online ordering etc.)
# Limited web page space.
# Your visitors may doubt your credibility.

There are also some more disadvantages.
> Long and hard-to-remember web address (instead of yourdomain . com)
> No branded emails addresses (you @ yourdomain . com)
> May not be free forever

disadvantages of free web host:

Little/No Support - Free web hosting providers generally offer no customer support to their free web hosting customers.
Overcrowded Servers - Often the servers web hosts put free users on may be overcrowded and slow or even frequently down.
Less Features - Free web hosting plans usually don't include advanced features, software, and email services that paid ones do.
Ad Banners - Many users find these ads take away from the design of their site, or are a nuisance to their visitors.

Thats bad news as I am working on developing my own site using free web hosting. Can anyone please reply me how long my website would be available on internet and whats are some other drawbacks regarding to free web hosting