No it cant no ST phones cant be tethered unless u want them to disconnect ur service but u can connect to a wi-fi ( read the fine print online about restrictions) i connect to my wi-fi at home as well ...
The short answer is NO. They will throttle your Internet speed or cut off your service.
The long answer:
Been a Straight Talk customer for about 8 months now, and this will be my last month with this carrier. What initially made Straight Talk attractive to me was their promise of unlimited talk, text and web for only $45/month, and being able to use my AT&T branded/locked Motorola Atrix HD Android powered smartphone.
The big problem with Straight Talk is that their service is NOT unlimited. If you exceed an unknown daily data/web usage limit, they will cut your Internet speed down to a crawling halt, making simple emails almost impossible. Some people claim it's 2GB/month before it happens - that's a myth. They have computers setup, that automatically calculate your usage on a daily basis, and the usage threshold is pretty low.
I have had this happen to me after one weeks use, and all I did was write emails, check Facebook, read news articles online and download a few app off the Google Play Store.
The next problem occurs when you call their support department. First you speak with a customer rep, who's accent is so thick you'll barely understand the person. They'll next tell you that you violated section 6 and 7 of the terms of service - which basically says they have the right to cut your Internet speed (throttle), or terminate your service if your data usage is 'excessive'.
Problem here being that they won't tell you exactly what 'excessive data usage' means, or at what point you reach that limit. When I asked them what the daily or monthly data usage limit is, and what amount of use would be considered 'excessive', the Straight Talk customer rep's answer was simply that the service is unlimited as long as your usage for data/Internet/text/calls is not excessive.
So there you have it folks - It's unlimited talk/text/data/Internet…Except it's not. And you'll have no idea when they'll cut you off, because they won't tell you, and it's not mentioned anywhere in their 'Terms of Service' (TOS).
For folks with dumbphones, this might be a good option for you, since you probably won't consume much data if any. However, if you have an Android, iPhone, Windows Phone, Black Berry, Nokia Symbian, or any other smartphone, you'll probably want to think twice, or trice, before going with Straight Talk, since you'll more than likely get into trouble with them sooner or later.
For the smartphone user who wants a cheap prepaid service, there are many other options than Straight Talk, and all of those alternatives will outright tell you what your data usage limit is before throttling occurs - if it occurs.
Both Boost Mobile and Virgin Mobile offer plans with 2.5GB of high-speed data before throttling, and T-Mobile just launched GoSmart Mobile, which offers a whole 5GB of data before slowing you down. With those companies, you'll at least know where you stand, and how much data you can consume before being throttled...
Yes with an app, but I wouldn't recommend it as Straight Talk says it's prohibited in their Terms and Conditions. and they might cut your service off.