A new report (pdf) by researchers at the University of Washington states that roughly one percent of web pages delivered to users are being manipulated in some way by ISPs. After studying some 50,000 computers, the researchers found that a select few ISPs were injecting ads into Web pages on their networks. The study found that the most frequent culprits are small ISPs like Texas's Redmoon, who used NebuAD technology to inject ads over existing ad relationships (NebuAD's CEO tells us they've since stopped the practice). From the research:The researchers have subsequently developed a web page tripwire system to detect ISP manipulation of web content they say is "more flexible and less costly" than switching to HTTPS for all traffic.