I've come across some transaction accelerators posted on form. How do these work? Are they scams?
if you're talking about the bitmain or viabtc accelerator: they are legit
viabtc and bitmain have a large mining pool (they own a reasonable percentage of the network's hashrate). They both created a web service in which a bitcoin user can make a request to prioritise their transaction on the pool's mining node.
With a higher priority, there is a larger chance the user's transaction will be added to the block either viabtc or bitmain is currently trying to solve. If their transaction is in a block, and either of these pools find a hash that is lower than the current diff, the user's transaction is confirmed.
If you're talking about other services (like transaction accelerator services offered on this forum), i guess at least 90% of them are using either viabtc or bitmain (or both).
However, there are a couple users like Quickseller and macbook-air that have push privileges to other pools, so if they offer a transaction accelerator service, they're also legit, but they don't use the free tools offered by viabtc or bitmain.
