Mercury in Virgo, the editor
Mercury in Virgo means a precise, practical mind that notices the details other people miss and wants to get things right. You think in steps, you see the typo before you've read the sentence, and you show care by fixing things.
Mercury covers thinking, speaking, learning and handling information. Virgo is mutable earth, and Mercury rules it, so this is one of the two signs where the planet is completely itself.
Ruler and exalted
Traditional astrology gives Mercury two signs, Gemini and Virgo, and in Virgo it's also exalted: the sign where a planet's best qualities are most honored. In plain words, Gemini is Mercury gathering information and Virgo is Mercury sorting it. Being both ruler and exalted here means the planet works without friction. It doesn't make you better than anyone else. It makes this the most Mercury-like Mercury there is, including its habit of never quite switching off.
The red pen
You reread messages before sending them, and sometimes after. You're the one who checks the group itinerary and spots that the train leaves from a different station. You notice the spelling mistake on the restaurant menu, the font that changes halfway down the poster, the step missing from the recipe. You keep lists, first on paper, then in an app, then on paper again because the app wasn't quite right.
You learn by method: a clear sequence, practice, feedback. People come to you when they need to know how to actually do something, because you explain it in order and you don't skip the boring part. Your humor is observational and exact, built on the small absurd detail everyone else walked past.
What you notice first is what's off by a little. Something is always off by a little.
Correction as care
The honest tension is that correcting people is a reflex, and it's how you help. You point out the error in the spreadsheet because you want the spreadsheet to be right, and the person who made it hears that they got it wrong. Your care arrives with a red pen attached.
The same precision turns inward. A sent email gets reread for mistakes at midnight. A finished piece of work isn't finished while one sentence could be better, so things go out late or not at all.
With your Sun
Your Sun is in Leo, Virgo or Libra, since Mercury is never more than a sign from it. With a Leo Sun, a confident, warm person has a quietly exacting mind behind the performance. With a Virgo Sun, the whole personality runs on getting things right, and rest comes hard. With a Libra Sun, the manner is gracious and the private notes are sharp.
The opposite placement, Mercury in Pisces, thinks in impressions where you think in specifics, and between them they cover the whole range of how a mind works. The Mercury sign guide shows how to find yours.
Questions
How does Mercury in Virgo communicate?
Precisely and usefully. You say exactly what you mean, in order, and you notice when someone else hasn't.
Is Mercury in Virgo smart?
It's an analytical intelligence built on attention to detail. It's excellent at finding the flaw, improving a method and explaining a process, and slower to leave a good-enough answer alone.
Is Mercury strong in Virgo?
Yes. Mercury both rules Virgo and is exalted there, which means it works with no friction at all. That's strength of character, not superiority: the precision and the worry come as a pair.