Well, that depends on the company. If they're providing me with a company phone for business, that's fine. However, I don't have a text plan, and I really don't want them texting me on my dollar, unless they'd be compensating my pay.
From a company's perspective, would it be effective and have enough of a benefit for the cost of doing so. At my current employer, we have cellphones setup for in-store use. Given that I'm all over the place, this is nice to have one while I'm there. I'm not management, but I need to have a way of being contacted by 10-20 people since I'm an inventory analyst.
When they want let the employees know, they post notices by the time clocks. I have a work e-mail address, but given that my boss on paper sees me maybe 30 minutes, 1 hour tops, a week, this, and the nature of my position are nice.