Much as they might love their iPhones, a lot of folks find it frustrating to try to find and read online news stories using Apple's devices, especially on Yahoo's mobile Web site, a new survey says.

Users of Apple's iPhone who frequently surf to some popular news sites face aggravations ranging from cluttered pages and excessive scrolling to search engine glitches, according to a new study from analyst firm Keynote Systems.

IPhone users taking part in Keynote's first ever "WebEffective for iPhone" survey were asked to rate their experiences on the Yahoo and Fox News mobile portals in several areas: finding an entertainment news story, reading an article online, and searching for a story on a particular topic, and then sending it to a friend.

After finishing these assigned tasks, only 64% of the iPhone users expressed satisfaction with the Fox News mobile site, and even less -- 51% -- with Yahoo's site. Similarly, about 60% of participants voiced "frustration" with the Yahoo site, as opposed to 33% of users for the Fox site.

As the analysts had anticipated going into the survey, users' pain points included cluttered pages, excessive scrolling, site errors, and "poor site speed," the Keynote analysts said in a statement. But the researchers came across some unexpected frustrations, too, including "lack of visual appeal" of the mobile Web portals and difficulties with search engine features.

Dismayingly for Web advertisers, both existing and potential, only four percent of the iPhone users clicked through ads. Almost one quarter of them did notice online ads, but decided not to click through them.