<p>I'm in favor of the merger. </p>

<p>Any questions which are specifically about deep neural networks, in contrast to neural networks in general, can be described as such in the text.</p>

<p>One motivation for the distinction <em>in the literature</em> is that training a network with more layers can be harder than training a network with fewer, among other similar types of problems (cf vanishing gradient etc). Recently, this challenge has been ameliorated (better initialization, activation, optimization and network wiring). Hence, deep neural networks are accessible to novice and expert practitioners alike, and given the success of deep networks in solving problems, it seems plausible to expect that scientists will tend to prefer using deep networks to solve problems going forward. That is, deep networks will probably come to envelope neural networks.</p>

<p>More to the point, as a matter of <strong>tagging</strong>, this distinction does not seem necessary. The purposes of tags is to organize posts; even though experts understand that deep and shallow networks are distinct, that fact doesn't imply that we need to preserve that distinction in <em>tagging</em>. If a person is in favor of maintaining the distinction, the justification must hinge on making the <em>tagging system</em> better.</p>

<p>On the other hand, combining the tags makes the usage clear and makes the organization less haphazard. Today, a user will search twice using <code>[deep-learning] keyword</code> and <code>[neural-networks] keyword</code>, or subscribe to both <code>[deep-learning]</code> and <code>[neural-networks]</code> tags. I don't understand why this is a good system when something like 90% of the <code>[neural-networks]</code> tags could plausibly also be <code>[deep-learning]</code> tags and vice versa.</p>

<p>Consider duplicate questions. If we commit to honoring the distinction between deep and shallow networks, can a general question about deriving back-propagation that bears the <code>[deep-learning]</code> but not <code>[neural-networks]</code> tag be closed as a duplicate of the same question bearing the <code>[neural-networks]</code> tag but not the <code>[deep-learning]</code> tag? On the one hand, the question content could be <em>identical</em> but for the tag, so decision Vote to Close as Duplicate may be obvious; on the other hand, if we reason that the distinction is vitally important, then we're signing up to double the number of questions under each tag. In the cases where the question <em>contents</em> are agnostic to network depth, this duplication is pointless from every perspective <em>except</em> that of tagging.</p>
