While combating online piracy is important, PIPA is the wrong way to do it. Under PIPA, a site accused (even under dubious claims) of copyright infringement can, under court order, have itself effectively censored from the rest of the Internet and its domain name blocked by ISPs. All links to the site must also be deleted.
Small businesses and independent artists, who benefit most from a free Internet but suffer most from infringement, will also find it difficult to start up due to fear of larger corporations abusing the bill.
The Obama Administration is more technically-savvy than Congress, and secured political victory in 2008 largely due to new media and viral campaigns. Surely the importance of a free Internet is something you understand. Please veto this un-American bill.