LinkedIn can grow in a few ways:
1. Partner with a freelance company to allow members to offer and obtain services through the LinkedIn brand itself
2. Create sub-brand platforms or portals where people from the same country can meet and network
3. Partner with training companies to offer online certificates and degrees, where you take courses socially and the activity becomes part of your network activity.
4. Partner with Skype/Google Hangouts to offer business calls, virtual meetings, webinars
5. Travel concierge services for business travelers, including connecting you with people in town.
All of the above should be managed with a point system, eg the more you participate the more points you earn, unlocking additional privileges.
Points should not be something you can purchase. They can make money from the sponsors of the various platforms offering services (eg for example Elance).
Addendum to #1, in response to a comment:
On #1 the idea would is to acquire a company (or companies) that already have the infrastructure for freelance. Elance, oDesk, People Per Hour come to mind. There is another company where you pay for a listening session by a CEO or equivalent but the name escapes me at the moment. TaskRabbit. Acquire, consolidate, brand under the LinkedIn umbrella, and actually allow people to buy and sell services at every price point.
All opinions my own. Originally posted to Quora.