For tech startups, are trademarks necessary?

Check out the cartoon we published on this topic: http://trademarkfactory.ca/cartoon/should_i_register_my_trademarks

What matters is not whether you are a startup or a tech startup, what matters is how important do you think the brand may be to your possible future success.

This is not a trick question to show you how wonderful trademarks are. This is an honest question you should ask yourself every time you are considering trademarking something. You don't get a trademark for the sake of getting a trademark. You get a trademark to minimize a risk of being forced to rebrand; to minimize the cost of going after someone who may be infringing on your brand; and to maximize the value of your business if you decide to sell or franchise it. If none of these concerns are important to you, don't bother with trademarks. If at least one is important to you, register your trademark.

Filing an EU Community Trademark is not so expensive and permits you to cover n.28 Countries. if you also file the same in CH you may have Rights in n.29 European Countries at a good price and, if they are granted they will last for ten years.

Its most-likely not necessary to file a trademark application if you suspect that the product name will change. Trademarks are not expensive but you need to register in each Country. If the name is important then you should trademark. If the product has global potential then file in all the key markets including China and there are tricks such as Chinese translation or phonetic translation that any competent trademark attorney will recommend.

1) If you are going to be frequently changing marks, registration probably doesn't add up on a cost-benefit analysis.
2) First use will only give you rights in certain jurisdictions; in others, whoever registers first has all the rights, regardless of use.
3) Owning the domain name is not a defence to trade mark infringement, so try to avoid other people's marks.

You've received some great answers so far, especially from Mr. Mincov. When you say that you are a "tech startup," I take that to mean that 1) your resources for investing in the establishment and enforcement of marks is limited and 2) marks and branding are not as important for selling your sophisticated and technical goods/services as they might be for goods which appeal to consumers based more upon subjective and emotional criteria. What is important for you to know is that you do accrue rights in a mark in the U.S. merely by using the mark; and registering that mark is not necessary in order to enforce your rights in it. However, a U.S. registration can reduce the cost of enforcing your rights since it 1) provides notice of your rights and is an effective deterrent against others using your mark; 2) becomes a form of evidence of your ownership and the validity of the mark; and 3) extends your rights in the mark throughout the U.S. instead of in only the markets where you actually use the mark. However, in many countries outside the U.S., you do need to register a mark in order to have any rights in the mark and in some countries, a mark needs to be registered in order to be able to use it.
That said, even without registering your marks I believe it is important and highly recommended that you at least initially consult with IP counsel to do your due diligence and ensure that you are using marks which are available and not at risk of infringing any other marks; you are using a mark that is protectible as a mark; and you understand what trademark or service mark "usage" is because trademark "use" is not a concept that is as straightforward as it seems. As Ms. Nichols alluded to, owning a domain name does not establish any trademark rights and is not itself use of a mark in Commerce. Only owning a domain name, posting marketing content on the referred website (if a service) and advertising the domain name as a mark is service mark use which establishes service mark rights. For goods, you have to actually affix the mark to the goods or its packaging in order to use a mark sufficient to accrue rights in it.
Moreover, you need to understand what is a distinctive mark which can acquire trademark/service mark rights v. a non-distinctive or generic mark which cannot be protected as a mark. Also, you mention using multiple iterations or variations of a mark or marks but will there be some consistency or element of those iterations that are sufficiently constant that consumers will recognize the marks as emanating from the same business and knowing that business is yours? Because if your mark changes too frequently such that consumers lose the ability to recognize the mark as identifying your particular company, then you effectively don't have a mark. The purpose of a mark is to identify your business as the source of the goods/services.
You want to make a sound business decision about this but you need to consider both long and short-term costs associated with your decision and investing in some expertise on this issue might be worth your while to avoid additional costs down the road.
*Please note my disclaimer in my bio.