General personal feeling: Yes, because it is fully operating on top of the Ethereum stack. Here is the related tag: augur, 7 questions asked this quarter.
Going through the example questions with highest score:
- Are there any hardware wallets capable of storing REP? [14]
Yes, REP is a token on the Ethereum platform, valid question and well on-topic.
- What is the difference between LMSR and Liquidity-Sensitive LMSR (LS-LMSR) and why has Augur decided to focus on the later? [14]
No, while I think everything Augur-related is on-topic, this question is simply not really related with Augur. The why part actually tends to start an opinionated discussion. Economics has this question: Difference between LMSR and Liquidity-Sensitive LMSR
- What is Airbitz Edge Security and what features does it bring to the Augur account creation process? [13]
Maybe, Airbitz Edge Security is an interesting authentication management system, however, as far as I know it's based on the Bitcoin platform. This question might also work out on Bitcoin Stack Exchange: questions tagged with [airbitz].
- Can I use Augur without owning REP? [13]
Yes, on-topic just like the first question.
- What is a Schelling Point and how is it relevant to Augur? [13]
Maybe, I'm no friend of what is questions, but at some point they are valid. 'What is a Schelling Point?' would be off-topic. However, 'How many transactions are needed to establish a Schelling focal point on the Augur platform?' would be on-topic.
- What is a stablecoin and why would it be of importance to Augur? [12]
Yes, A valid canonical question which is put in context of Augur. Here is the Ethereum version: How would stablecoins work on Ethereum?
- What advantages does the Serpent programming language offer Augur developers compared to Solidity? [10]
Yes, both serpent and solidity are native Ethereum programming languages.
- How many REP tokens exist and will the supply ever change? [10]
Yes, on-topic just like the first question.
- Is there a procedure for challenging the decision of reporters? [10]
Maybe, this is a very specific question which would be on topic for Ethereum Stack Exchange, but (if existing) better suited for an Augur-specific site.
- What is the origination and meaning of the name Augur? [10]
Yes, as Augur is on topic.
Going through the questions confirms my personal feeling, however, this does not imply that I think there should be no separate Stack Exchange site for Augur. That's up to the community.