I truly wish you luck in your fight against Instagram. Name stealing is a rough game. I know because I have been traveling on Bolt buses for 8 years now (http://www.boltbus.com/). I know there is some confusion because you have basically the same symbol. Maybe there aren't too many ways to vary a lightning bolt shooting through an "O" in the word "Bolt" but I welcome you (and Instagram to try).
Sincerely, A bus rider.
As bolt.co is claiming, there are many people who appear to be confused between instagram's offering and the company's product (they are arguably in the same space and possibly competitors).
For example if Microsoft Combine Harvesters popped up, it would be relatively straightforward to argue that they are making use of the Microsoft mark for the sole purpose of attracting attention to its product, by effectively piggy-backing on the real Microsoft's reputation.
Proving reputation is difficult but generally you will have to show substantial investment in marketing/advertising in the relevant territories.
If I can't show reputation I am limited to actions for straight infringement (identical mark/identical services/goods) or confusion-based actions (similar mark/similar services/goods).
A good example was the Budweiser v Budvar saga http://en.wikipedia.org/wiki/Budweiser_Budvar_Brewery#Tradem...
Generally, you would hope that the parties could come to an agreement and enter what's known as a co-existence agreement where they just agreed to continue but in some cases agree not to further encroach on each other's markets for example.
The above example just ran and ran with each filing suits around the world, showing the difficulties of deciding who should have sole rights to a name when both have built up substantial goodwill over a long period of time.
Side Note: trademark protection is more focused on protecting consumers than companies - unless the company has spent an excessive amount promoting and selling their products, at which point, they are given special protection/rights.
(I'm amazed The Beatles let them get away with it).
So, while I get your intention, that's not how trademarks work. If Bolt doesn't have a trademark, they should stop complaining.
From recent cases I only remember Microsoft to change their mind in regards to their "Metro" OS. However, even in that case Microsoft decided to back off because "Metro" was a big retailer that sold Microsoft's products, so bad blood could cause bottom line to take a hit.
I'm curious who got this name earlier.
Bolt.cm registered 2012-09-19
Bolt.cd earliest record 2011-01-04
Bolt Bus will definitely not be confused with the Bolt App.
Bolt (the Disney movie): http://cdnvideo.dolimg.com/cdn_assets/abd7aa3a4851f515796d9d...
Bolt Browser: http://en.wikipedia.org/wiki/Bolt_(web_browser)