The following thirteen(!) users: 

<a href="https://mathoverflow.net/questions/330472/functors-reflecting-colimits">goingfullscheme</a>  
<a href="https://mathoverflow.net/questions/330404/when-are-valuative-criteria-useful">valua_aint_no_galois</a>  
<a href="https://mathoverflow.net/questions/330390/schemes-admitting-a-cover-by-isomorphic-affine-opens">going-full-isomorphic</a>  
<a href="https://mathoverflow.net/questions/330390/schemes-admitting-a-cover-by-isomorphic-affine-opens">logicians_rule</a>,  
<a href="https://mathoverflow.net/questions/330215/reading-off-the-geometric-properties-of-a-proper-scheme-from-its-affinization">martintzar</a>   
<a href="https://mathoverflow.net/questions/330207/are-geometric-conditions-open">royalroadtogeometry</a>   
<a href="https://mathoverflow.net/questions/330178/a-slightly-canonical-way-to-associate-a-scheme-to-a-noetherian-spectral-space">bundlist</a>   
<a href="https://mathoverflow.net/questions/330168/compact-quasi-coherent-sheaves">compactbut</a>   
<a href="https://mathoverflow.net/questions/330159/noetherian-stalks-imply-locally-noetherian">faptoint</a>  
<a href="https://mathoverflow.net/questions/330000/finite-picard-group">you_dont_mess_with_ron</a>  
<a href="https://mathoverflow.net/questions/329997/affine-open-with-irreducible-complement">ron_is_striking_back</a>  
<a href="https://mathoverflow.net/questions/330453/algebras-such-that-the-tensor-product-with-any-noetherian-algebra-is-noetherian">Emmy_to_Noether</a>   
<a href="https://mathoverflow.net/questions/330337/noetherian-and-finitely-generated-for-polynomial-algebras">commutative_drinker</a> 

(and, I believe, a couple more besides) have the following characteristics in common:

<ul>
<li>They've all joined in the past few days.</li>
<li>Most have asked exactly one question and none has asked more than two</li>
<li>Their questions are closely related to each other</li>
<li>Their writing styles are very similar</li>
<li>After posting their questions, they never return to engage with commenters, or to acknowledge answers</li>
</ul>

I think it is not too much of a leap to conjecture that these are all the same person.  

As far as I know, there's no actual rule against having fifteen different identities (or for that matter, a hundred, as seems likely if this keeps up at this rate for a few more weeks), and no actual rule against asking questions and then systematically ignoring responses, but I still find it troubling in ways that might or might not be entirely rational on my part.  Do others share my discomfort?