It's also worth noting, the best ships for speed tanking are ones that get a reduction in signiture bloom from a MWD.
Generally, trying to Speed tank in a cruiser/battlecruiser is a bad idea for a number of reasons
Most importantly turning your MWD on makes you easier to hit because of the increase in your signiture size, a cruiser with a MWD on (with notable exceptions) is easy pickings even for a modest skilled pilots battleship guns.
You are moving fast, therefore you will also have trouble tracking and hitting them! Training Sharpshooter, surgical strike and other gunnery support skills will help here though.
You are Capacitor dependant, therefore you will have a hard time doing this if your energy manangement skills are poor, especially if you are an Amarr player.
You are still alot bigger and slower than a frigate or destroyer (this really goes without saying), but it's worth noting that again with the odd exception don't expect to go more than about 1500m/s where as the vagabond and inty's can easily get 4000+ with good skills.
The counter to a speed tank is the Amarr Curse, or on normal ships energy neuts (although good pilots can stay out of range of the latter, and remain combat effective) due to reason number 3 you take away their capacitor and they can't run their MWD anymore.
Spider tanking as pointed out is a web of remote reps that work because remote repping is more energy efficient than local repping (as to say you get a better tanking from someone else repairing you than you do repairing yourself).
You usually see this on a group of battleships, carriers or logistics, and is so called due to the fact that the repair effect between all the ships sprawls out like a spiders web.
As pointed out above it's usually done on armour tank for efficiency and a good well organised spider tank can be nearly unbreakable with pure DPS.
The counter to a spider tank lies in the Caldari Falcon or Widow or one of the Heavy ECM boats, you jam as many of the ships as possible, as the tank relies on the fact that they can keep each other locked to work, therefore break their connection to one another, break the tank.
Hope this helps?