By now you must know about Tango, a coming update to the Windows Phone smartphone line that will lower its minimum system specifications. By doing so, Tango will allow for cheaper handsets to be built, opening new markets for the platform. More markets, in theory, means more sales.

Consider Tango Microsoft’s shot at the low-end of the cellphone market, a place that traditionally, smartphones do not tread.

However, there is a cost to using one of the Tangoed, cheap devices: limited functionality. There’s a reason that Microsoft had system requirements where they were, and so now that they are lowered, certain things have had to be cut. Of course, on normal Windows Phone devices, these restrictions do not apply. The excellent LiveSide dredged a list from Microsoft’s notes, take a look:

  • Windows Phone Marketplace app restrictions – Some processor-intensive apps have memory requirements, and won’t work on phones with 256 MB of RAM. You can check how much memory you have on your phone by tapping Settings > About.
  • Podcast Subscriptions and Video Podcasts – You won’t be able to manage podcast subscriptions on your phone or watch video podcasts if your phone has 256 MB of RAM.
  • Local Scout – You won’t be able to use Local Scout if your phone has only 256 MB of RAM.
  • Fast app switching – This feature will not work if your phone has 256 MB of RAM.
  • SkyDrive automatic photo upload – You won’t be able to upload pictures automatically to SkyDrive if your phone has only 256 MB of RAM.
  • HD video playback – You won’t be able to play video compressed with some of the listed codecs if your phone has 256 MB of RAM.

That’s quite the list. As a side note, that Local Scout is being excised is not a surprise; that app lags like a beast on every Windows Phone handset that I have tested it on. How bad are the restrictions? We say that despite their number, the assortment of restrictions is rather feeble; Windows Phone will be recognizable, even on the cheapest handsets.

With phones such as the Nokia Lumia 900 at the top, and a coming slew of inexpensive handsets, Window Phone is doing it right, but will the buyers materialize?