Join for FREE,
and start talking with other members, weighing in on community polls,
Also, by registering and logging in you'll see fewer ads and pesky
welcome messages (like this one!)
No they aren't, not to employers. They both provide the same skills (if you want to call them that), reading, writing, and some critical thinking.
There isn't anything one could do that the other couldn't. So having both would just be repetitive and useless.