Breakdown of Við viljum ekki slíka samfélagsmiðla.
ekki
not
við
we
vilja
to want (to will, be willing)
slíkur
such
Questions & Answers about Við viljum ekki slíka samfélagsmiðla.
Why is slíka used here instead of slíkur or slíkt?
Slíkur must agree in gender, number, and case with the noun it modifies. Here, it modifies samfélagsmiðla (social media), which is a masculine plural noun in the accusative case (as the direct object of the verb vilja). Therefore, we need the masculine accusative plural form, slíka.
If I wanted to use svona instead of slíkur in this sentence, how would the grammar change?
If you used the more conversational svona (or þannig), the word itself wouldn't change at all because those words are invariable (they never decline). The sentence would simply be Við viljum ekki svona samfélagsmiðla. This is why slíkur is trickier to use in formal writing; it forces you to apply the correct noun declension.
How does the word samfélagsmiðla break down, and why does it end in -a?
It is a compound of samfélag (society) and miðill (a medium/channel), joined by a genitive -s-. The base word miðill is a masculine noun that becomes miðlar in the nominative plural. Because it is the direct object of viljum, it takes the accusative plural ending, making it miðla.
Word order check: Could I put ekki at the very end of the sentence?