• by Wendy Davis , Staff Writer @wendyndavis, March 20, 2015

The ink wasn't even dry on the Federal Communications Commission's net neutrality order when HBO announced a new stand-alone service that highlights the rules' weaknesses: Broadband providers can still take aim at rivals by capping the amount of video consumers can stream.

Last week, HBO unveiled a $15-a-month service that will allow cord-cutters to view programs like “Game of Thrones,” “Girls,” and “Silicon Valley” online. But people might not be able to do so without paying for extra bandwidth, depending on what types of data caps cable companies and telecoms impose.

The net neutrality rules don't currently prohibit broadband carriers from setting data caps. Already some phone carriers impose pay-per-byte billing at rates that make it impractical to watch much video via the data network. AT&T and Verizon, for instance, no longer allow new subscribers to sign up for unlimited data. Instead, the companies offer pay-per-byte plans. While the specifics vary, watching an entire season's worth of programs could add up very quickly under any of the plans.

Wireline carriers that impose data caps typically offer more generous ones of around 150-300 GB a month. But carriers could lower their caps at any time. And even the current caps aren't enough for people to completely replace video with high-definition streams -- which would take at least 684 GB of data a month, according to the advocacy group Public Knowledge.

In the past, some mobile carriers have allowed some content companies to purchase “sponsored data” -- meaning that the companies pay to have their data excluded from consumers' caps.

HBO is now hoping to be exempted from broadband providers' data caps, as are Sony and Showtime, The Wall Street Journal reports.

It's not clear whether broadband carriers will agree to do so, or even if those deals will be considered legitimate. The Federal Communications Commission's new net neutrality rules provide that the agency will examine sponsored-data arrangements on a case-by-case basis.

Today, Republican Commissioner Mike O'Rielly, who voted against the net neutrality rules, questioned that approach.

“OTT video dilemma: beg @FCC for blessing or hope for best?” he tweeted, referring to over-the-top video services. “#NetNeutrality puts innovation in question.”