More and more Paddlers, Sailors, and Kayak Sailors are carrying communications equipment with them on the water.
For years I've carry a handheld VHF at the coast and a Cell phone on inland fresh waters. The VHF is very handy where I paddle at the coast of North Carolina because the Coast Guard has high towers and good radios and I can communicate with them anywhere I go. I can also communicate with any boat I see and some that I cannot see. So for the places I go the VHF works well.
On the lakes and inland rivers vhf does not work well and the best way to communicate in the past has been to hike to high ground and get a cell phone signal. I've been able to get a text out from anywhere in the state in the past year be walking to the top of the nearest hill. Down on the river cell phones do not work as well.
I've seen SPOT's used quite a bit for tracking of races and adventurers, but they do not seem reliable enough to be life safety equipment.
EPIRB technology has gotten smaller and cheaper and now you can get a PLB that is very reliable for about $300.
What worries me is that folks think they can press the button and get help just like when you call AAA from the city for your car. In the wilderness you may be hours or days from help. I worry that folks who have these items may take unneeded risks that they should not.
In almost every case I am familiar with I feel that training and prevention would have been better than carrying the SPOT, PLB, or VHF and depending on the help of others. I'm interested in others take on this so if you disagree, please be sure to leave a comment.