Firstly, when did http://cl.ly/image/192x1c3L3B0d become the model for success?

What it really comes down to is this:

1. You're left with an app that has stagnated in market share for a number of years (even dropped a bit)

2. Your brand has been marginalized by Facebook's vertical integration of your primary feature

3. You have some money left (investment, revenue, whatever - I don't know about Foursquares's finances, but they obviously have some money or they'd be gone)

Given the aforementioned, do you A) pretend like nothing happened and continue watching your brand fade into obscurity (e.g., MySpace), or B) try to reinvent (e.g., like MySpace did - their traffic topped 55M uniques/mo in 2014)?