Dropbox has reached an amazing milestone of 100 million users after five years of running strong.

They announced this today in a blog post from the founder Drew Houston and also announced that they would be giving 10 gigabytes away free to the Top 100 winners of their user story competition and 100 gigabytes to the Top 10.

For those of you who do not know, Dropbox has been one of most successful cloud storage companies and really pioneered the technology before larger companies like Google entered the market completely.

So what do all of you think?  Are you a member of Dropbox and if so, why?