How does a Titan "support"?

I'm still new to the game but when trying out the Monarch Titan for the first time I got a little confused by the idea of support when it comes to Titans. How does a Titan support in this game? Tank makes a lot of sense since they could have larger health pools and higher shield numbers (not sure if this is true but I would assume so) but other than the one ability where Monarch can shoot an ally to give them shields, how do Titans support?

1. Has anyone made use of the Monarch ability to shoot allies to give them shields? How viable is this in fun/competitive play?

2. What are ways that Titans can support other than the ability from question 1?

3. Am I correct in my assumptions about tank shields and life for tanks?