Pros
Strong Culture where stated Values are adhered to at almost every level. Exceptions are few and stand out like sore thumbs. Employees are allowed a good amount of autonomy (sometimes manager dependent) and there is a level of trust between Executive Leadership and the individual contributors that I've not seen at any other company I've been at. While it's certainly no longer a start-up, Employees are given mind share to introduce intelligent change into the organization. Great benefits package.
Cons
I second what others have said about career opportunities outside of Global HQ in Mountain View / Sunnyvale. If you want to do something other than Sales, you have a steep uphill battle ahead of you. And anything outside of teams that directly support the Sales Organization is out of the question. LinkedIn is a very Engineer-driven company, so most decisions are made without input from other teams or clients. And most roles outside of Engineering pay below market standards, but this is softened somewhat by an overall strong benefits package. It's a young company, so retirement benefits flat-out suck.