IYW Reddit Mentions | ChartExchange

QQQ is honestly a pretty weird fund when you dig into it, and it's only as popular as it is thanks to being there first and the way GICS classifies companies.
VOO is purely market cap weighted and as neutral as a single-country US bet can bet. Owning it isn't making any statements about sectors or technical strategies, you just own the market. It is legally classified as a diversified fund.
QQQ tracks the 100 largest market cap stocks on the Nasdaq (the Nasdaq-100 index) only, using the weights published by that Nasdaq. This has never strictly been market cap weighted, and the Nasdaq has fiddled around with their methodology a lot over the years (and has dispensation to arbitrarily change the rules for their index weights in 'exceptional circumstances'). For example, under the rules they've introduced recently to benefit SpaceX specifically, companies with a tiny float can be up to tripled - so QQQ is forced to buy three times more SpaceX than is reflected by the actual pool of available shares.
QQQ has become fairly socially acceptable for self-described 'passive' investors to slot into a portfolio for 'aggressive growth', but it's really just a proxy for US megacap tech, or a way to overweight the Mag7 within a portfolio. In reality the Nasdaq-100 is just the top 100 companies on the Nasdaq exchange excluding financials (so you get Kraft Heinz and Costco with the tech), which is a fairly arbitrary classification. Nobody obsesses over a hypothetical 'only certain NYSE-listed stocks' fund the way they do over QQQ.
The reason it's not done more cleanly through a market cap-weighted tech vehicle is because under GICS rules, Google and Meta are counted as communications companies, and including that sector with technology would bring in the likes of Verizon. Tesla and Amazon are classified as consumer cyclicals, and you can't add that sector to a tech etf without bringing in Home Depot. The Nasdaq corresponds fairly roughly to what consumers imagine a 'tech company' is, so buying it is the default.
QQQ isn't the default because it's a specific bet on weightings set by the Nasdaq exchange, which companies list there and mega cap tech continuing to dominate. None of that is actually all that passive. Legally they're not even classified as a diversified fund. IYW is arguably a better expression of what retail buys QQQ for, and if you look at it and go 'that looks too concentrated', you shouldn't be buying QQQ either.
**TLDR; VOO is a real passive fund, QQQ is a mild form of active investing for people who like to think they're bogleheads without honestly engaging with the higher potential risk and reward.**