While Clearwire's Clear Mobile WiMax often delivers speeds of 8-12 Mbps, several customers have written in to us to note they're having their speeds throttled back substantially. While network management is not unexpected, it appears that Clear isn't being particularly, well, clear about what triggers this throttling. Clearwire's acceptable use policy reads the same as most ISPs' -- giving them the right to throttle users during periods of congestion:Users both in our forums and over at the official Clear forums are running into these limits, though again, Clear isn't getting specific about exactly how much usage is considered excessive, or how far back users should curtail use if they're looking to avoid the throttle monster. We've contacted Clearwire in the hopes of getting more specifics from the company in terms of what they consider excessive use, and/or what triggers "ISDN mode," but have yet to hear back. One user writes in to Broadband Reports:The company's AUP only goes so far as to insist that "the continuous unattended streaming, downloading or uploading of videos or other files" is prohibited. While limits on capacity-limited wireless networks aren't shocking per se -- invisible limits with no clear trigger does run in contrast with company statements that their "unrivaled spectrum position" allows them to offer truly unlimited service.