Recently the EFF has exposed a company for inflight modification of URL bar based searches. Paxfire has been linked to at least 9 American ISP's and sells ads for inflight modification, simply put, they screw with the results of the searches u do. Now this is mostly possible due to the way modern day search engines work, as cloud services. Most cloud services do inflight modification but they pretty much all do not do it for the purpose of interception. A Extensive study has setup and follow this for a while and confirmed 9 ISP that take part in this scam. The actually scam, is when u have your browser u have the URL bar, normally when u type in there and hit search it will take you to your default search engine,   yahoo, bing or google. This services allows the query to be modify returning more relevant results for the ISP advertiser's in hand making them more money. PaxFire isnt exact 100% clear to everyone on what they do, as they say

At its core, Paxfire is an easy-to-implement search results service that enables you to generate significant revenue with the traffic that’s already on your network. Your users get a positive experience and you tap into the profit other companies are currently making from your network customers.

As the industry leader in monetizing Address Bar Search and DNS Error traffic for Network Operators, we offer three fully customizable solutions to allow ISPs to begin generating new ad revenue immediately: Now, while there is nothing wrong from making money from advertising, as long as u do it ethically and let the user know they are taking part in it. This service and these ISP's do no such thing. In the research documents released, they talk of over 4000 different IP's that are possible rouge servers intercepting data. So this really leads me to ask, what else does our ISP sell? How can this be classed legal in any way possible, If a hacker is found guilty of playing with a network, then why isn't an ISP or a company like Paxfire found guilty of data interception. I wont bother re writing what everyone else has so here is the original research documents on this, Article from the EFF