Simple is; no one interested in it ie; 1.5m volume in a .007 bid is worth= $10.5k total that bid @ .007 is $5810= one will spend that that ask @ .017 is $1360= one will sell that
The one that wants to buy isn't willing to buy @ .017 The one that wants to sell isn't willing to sell @ .007
"And is it a good thing or a bad sign?" Most cases= BAD= lack of liquidity= lack of demand ie; I hold a garage sale (ask) & am selling cd's @ the price I paid for them= $10. You the buyer (bid) say I'll give you a buck $1 buy/sell or walk??
If there were a demand for my cd's, they either pay my ask or offer (bid) $9.90 or so. If not, the current of said cd's/stock is what someone is willing to pay for it=(bid)
If the demand= volume was good, the spread would be a lot closer.